Evaluates: MAX17100
logic-low. When their input logic is high, STH1 and
STH2 output is connected to GHON; CKH1 and CKBH1
output is connected to GHC1; CKH2 and CKBH2 out-
put is connected to GHC2. GHC1 and GHC2 are the
output of the two high-voltage switching blocks.
The six switches within SW1 select logic levels on
inputs ST1, ST2, CK1, CKB1, CK2, and CKB2 for test-
ing purposes. Set each switch open when driving the
inputs with external logic. Jumpers JU14–JU19 are
used to select between capacitive loads on the outputs
for testing purposes.
IN Power Supply (JU2)
The MAX17100 IN pin can be supplied directly from the
VS pad or from an on-board linear regulator through
configuration of jumper JU2. See Table 1 for jumper
JU2 configuration.
Level-Shifter Logic-Level Inputs
(JU6–JU11)
The MAX17100 level-shifter inputs can be supplied
using the on-board logic or from an externally applied
signal through configuration of jumpers JU6–JU11.
Additionally, when using on-board logic, SW1 controls
the logic levels based on its own settings. When SW1 is
on, the logic input is high. When SW1 is off, the logic
input is pulled low through a 100kΩpulldown resistor.
See Table 2 for jumper configuration.
Level-Shifter Output Loading (JU14–JU19)
The MAX17100 EV kit incorporates jumpers JU14–JU19
to provide loading options at the level-shifter outputs
(STH1, STH2, CKH1, CKBH1, CKH2, and CKBH2). See
Table 3 for jumper configuration.
Output-Voltage Selection
The MAX17100 EV kit’s step-up switching-regulator out-
put (VMAIN) is set to +14V by feedback resistors R56
and R57. To generate output voltages other than +14V,
select different external voltage-divider resistors, R56
and R57. Note that changing the VMAIN voltage setting
changes the VGOFF and VGHON charge-pump output
voltages. Refer to the
Step-Up Regulator, Output-
Voltage Selection
section in the MAX17100 IC data
sheet for more information.
Detailed Description of Software
The MAX17100 device includes a calibrator used for
adjusting an LCD’s backplane voltage (VCOM) in TFT-
LCD displays. The VCOM voltage is adjusted by con-
trolling the amount of sink current drawn by the
calibrator. This is accomplished by programming the
desired setting into the device’s 7-bit internal DAC. The
software also facilitates reading of the device and pro-
gramming of the device’s internal nonvolatile memory.
Refer to the MAX17100 IC data sheet for further details.
Loading 7-Bit DAC Setting
The DAC setting corresponds to a certain sink-current
level, which in turn corresponds to a specific VCOM
voltage. With the MAX17100 EV kit software, the
device’s 7-bit internal DAC is configured by entering an
appropriate DAC setting into the Load DAC edit box.
The DAC setting can be set from 0x00 (VCOMMAX) to
0x7F (VCOMMIN). The DAC setting is written to the
device by pressing the Load DAC button (Figure 1).
Reading 7-Bit DAC
The MAX17100 7-bit DAC can be read by pressing the
Read DAC button or by checking the DAC polling
checkbox. When checked, the software continuously
reads and displays the DAC’s current setting.
Programming Nonvolatile Memory
The current DAC setting can be programmed into the
device’s internal nonvolatile memory by pressing the
Program button. Each time the device is powered-on,
the DAC is loaded with the setting stored in the
device’s nonvolatile memory. Programming is only pos-
sible when GON is greater than 16V and WR# is low.
MAX17100 Evaluation Kit
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